The semiconductor integrated circuit (IC) industry has experienced rapid growth. Over the course of this growth, functional density of the devices has generally increased while the device feature size or geometry has decreased. This scaling down process generally provides benefits by increasing production efficiency, lowering costs, and/or improving performance. Such scaling down has also increased the complexities of processing and manufacturing ICs and, for these advances to be realized similar developments in IC fabrication are needed.
Likewise, the demand for increased performance and shrinking geometry from ICs has brought the introduction of multi-gate devices. These multi-gate devices include multi-gate fin-type transistors, also referred to as FinFET devices, because the channel is formed on a “fin” that extends from the substrate. FinFET devices may allow for shrinking the gate width of device while providing a gate on the sides and/or top of the fin including the channel region.
Another manner for improving the performance of a semiconductor device is to provide stress on or strain to pertinent regions of the device. Manipulating the stress provided in a region is an effective way of improving the minority carrier mobility in a FET device. When stress is applied to a channel of a semiconductor device, the mobilities of the carriers can be affected and as such the transconductance and on-current for the device altered. For example, tensile stress may benefit an NFET device allowing increased mobility of the carriers (e.g., holes) through the channel region. Conversely, compressive stress may benefit a PFET device.